42
2 Environment Analysis of Lunar Soft Landing Exploration
Table 2.9 Conductivity of lunar rock sample
Lunar rock
σ 0 /(S/m)
E 0 /eV
σ 1 /(S/m)
E 1 /eV
10048
3.5
0.896
2.66 × 10 −3
0.559
12002, 85
13
1.09
1.80 × 10 −4
0.48
15058
134
1.347
2.78 × 10 −3
1.593
15418
137
1.509
9.84 × 10 −2
0.971
15555
36.8
1.040
1.27 × 10 −2
0.604
68415
1.27 × 108
2.640
0
0
68815
14.2
1.366
0
0
soil conductivity of infrared region increases 10 times and that of ultraviolet region
increases 10
6 times when comparing to the conductivity at night.
2. Complex Dielectric Constant of Lunar Substance
Lunar substance is typical silicate medium. The two complex numbers that scale
the characteristics of medium are complex dielectric constant ε* and complex
permeability μ*:
ε
∗
= ε 0 ε r = ε 0 (ε
− jε
)
(2.12)
μ
∗
μ = μ 0 μ r = μ 0 (μ
− jμ
)
(2.13)
where: ε 0 is the vacuum medium constant and μ 0 is the vacuum magnetic
permeability.
δ ε and δ μ are defined as the electric loss angle and magnetic loss angle of the
medium material, respectively:
tan δ ε =
ε
ε
(2.14)
tan δ μ =
μ
μ
(2.15)
where ε’ is the real part of the complex dielectric constant and is often called as dielectric constant or capacity. It is the major macroscopic physical quantity that comprehensively expresses the polarization of medium and the capability of substance to
store magnetic energy. ε” is the imaginary part of the complex dielectric constant
and is related to conductivity. It is expressed as
ε
=
σ
ωε 0
(2.16)
where σ is the conductivity and ω is the angular frequency of electromagnetic wave.